Abstract

Exciton-phonon coupling and electronic overlap (excitation transfer) are known as the competing mechanisms in the exciton-phonon problem, which become apparent in the optical lineshape of excitons. A phenomenological treatment of this problem yields a Lorentzian lineshape for weak exciton-phonon coupling and a Gaussian for strong coupling.¹ We have studied the lineshape of excitons by evaluating Kubo's expression for the optical susceptibility using the projection-operator formalism. In general, this theory yields asymmetric lineshapes due to a frequency-dependent memory function.

© 1984 Optical Society of America